Dim Weight Details



Differences in Actual and Dimensional (DIM) Weight

What's the difference between actual weight and dimensional (DIM) weight? Like, why are some packages of light, corrugated plastic blanks calculated at a higher weight?

Shipping carriers consider actual weight to be the package weight, sometimes rounded up to the next whole pound if it falls in between. That's simple enough. Dimensional (DIM) weight, however, takes into consideration the amount of space a package occupies in relation to the actual weight of the package. Carriers compare the dimensional weight of a package to its actual weight and in most circumstances use the larger of the two to determine the billable weight. UPS, FedEX and US Postal Service all do this. DIM weight is the new normal. In January 2015, carriers started to use dimensional weight to calculate the cost of shipping ALL packages. And In January of 2017, they raised the rates again. Typical large items that cause issues are listed under 'Problem Children' below.

Here's how carriers determine dimensional (DIM) weight:

Determine the package dimensions in inches. For each dimension, measure at the longest point, rounding each measurement to the nearest whole number. For example, 1.01 to 1.49 would be considered 1 and 1.5 to 1.99 is two, etc.

Measure the length, width and height of the package at its extreme points. (If there's a bulge or the package is shaped irregularly, always include the bulge or irregular part of the package in the calculation.) Multiply the package length by the width by the height. (L x W x H) The result is the cubic size in inches.

For domestic ground shipments: Divide the cubic size by 139 to determine dimensional weight in pounds. Compare the calculated DIM weight to the actual weight. Use the weight, rounded up to the next whole lb, that is higher to calculate the cost of shipping. UPS DIM Calc FedEx DIM Calc & Info


Why is understanding how carriers use DIM weight important? Sometimes the dimensions of the package override the actual weight and your shiping costs from the carriers are a whole lot more than you expected. For example, here's how the amount of space the package occupies – not its actual weight – impacts the cost of shipping:

Ship Method / Destination: Ground / Domestic
Actual Weight: 32 pounds
Length: 30 inches
Width: 15 inches
Height: 15 inches
Cubic Size Calculation: 30 x 15 x 15 = 6,750 cubic inches
Dimensional Weight Calculation: 6,750/139 = 49 pounds

This package is being shipped domestic ground. It's cubic size in inches is divided by 139 to determine the dimensional weight, which is 49 pounds. The DIM weight, 49 lbs, is larger then the actual wight of 32 lbs, so the dim weight would be used as the billable weight.


Some typical 'Problem Children' that occupy a larger dimensional space, thereby overriding their actual weight and resulting in higher shipping costs:

24" x 18" and 36" x 24" Corrugated Plastic Sheets, Wind Sign II, Signicade, Squarecade, Econo Sign, Deluxe Signicade, Floor Racks and Wall Racks.